In U.S. Pat. No. 4,821,832 entitled MOTOR SCOOTER HAVING A FOLDABLE HANDLE AND FRICTION DRIVE of Steven J. Patmont Issued Apr. 18, 1989, there is disclosed a hydraulic fluid coupling or torque converter. This fluid coupling includes an inner motor driven shaft, an outer wheel driving shaft, and a fluid couple between the driven and driving shafts for producing in a motor scooter a fluid drive.
In U.S. patent application Ser. No. 08/136,440 entitled FLUID COUPLING FOR SMALL ENGINE WITH DIRECT WHEEL DRIVE, now U.S. Pat. No. 5,494,128 issued Feb. 27, 1996, a fluid clutch is illustrated. Summarized, a fluid coupling is disclosed for the direct drive of a wheel from a small engine. The fluid coupling is mounted in cantilevered support or two ended bearing support from a small engine and has a small diameter inner driven shaft and a larger diameter outer wheel driving shaft for contacting and directly driving a wheel. The inner driven shaft connects to a pump having a relatively larger outer diameter than either the driven or driving shaft. This pump is mounted on the opposite side of the driven wheel from the engine and preferably includes rotating vanes within one half a toroidal path having an attached eccentrically mounted toroidal plug for causing helical rotation of fluid about the plug. A turbine mates to the pump and includes rotating vanes within the other half of the toroidal path, these vanes being shaped around the toroidal plug of the pump. The toroidal plug and toroidal volumes are eccentrically mounted one with respect to another to cause high velocity flow on the outside diameter of the pump and turbine with low velocity flow in the inside diameter of the pump and turbine. Fluid, typically oil, is confined to the pump and turbine by appropriate seals and causes torque conversion between the pump and turbine. In the preferred embodiment, a fuel tank for the engine is mounted overlying the driven wheel so as to shield the interface of the wheel and driving spindle. At the same time, the exterior of the driven pump is supplied with vanes to generate appropriate air cooling at the fluid coupling. A preferred embodiment is disclosed wherein the mount of the fluid coupler includes a bearing on the outboard end of the fluid coupler. The above entitled Patent Application is incorporated herein by reference.
Normally, small engines contain their own pull starter. Typically, such a starter has a conventional spring actuated retraction mechanism. To start the engine one pulls; to retract the starter cord, one carefully releases the cord.
Combined with a fluid clutch, and applied to a direct drive, two disadvantages are present. First, where the pull starter fails, compression starting the engine through a fluid clutch is all but impossible. Specifically, the vehicle powered by the engine has to be move almost at full speed to permit the clutch to transmit sufficient power to the engine to self start the engine. Secondly, there is no way to use the compression of the engine as a dynamic brake.
In what follows, an improvement on this fluid clutch is disclosed.